When laying wiring you need to know, the cable with the cores of which section you will need to lay. The selection of the cable cross section can be made either by power consumed, or by current consumed. Also consider the length of the cable and the laying method.
Select the cable cross section
You can choose the wire section in the power of the devices that will be connected. These devices are called the load and the method may still be called "on load". The essence of it does not change.
The selection of the cable cross section depends on the power and strength of the current
We collect data
To begin with, we find in passport data of household appliances consumed power, write it down on the leaflet. If it is so easier, you can look at the nameplates - metal plates or stickers fixed on the body of equipment and equipment. There are basic information and, most often, power is present. Identifying it easier by units of measurement. If the product is manufactured in Russia, Belarus, Ukraine is usually worth the designation of W or kW, on the equipment from Europe, Asia or America, it is usually an English designation of watts - W, and the power consumption (it is necessary) is denoted by the reduction of "TOT" or TOT MAX.
Example nameplate with basic technical information. Something similar is on any technique
If this source is not available (the information was lost, for example, or you only plan to acquire equipment, but have not yet been determined with the model), you can take the average data. For convenience, they are reduced to the table.
Table of power consumed of various electrical appliances
Find the technique that you plan to put, write out the power. It is sometimes given with a big scatter, so it is sometimes difficult to understand what figure to take. In this case, it is better to take a maximum. As a result, during the calculations, you will have a slightly overestimated power of the equipment and the larger cable will be required. But to calculate the cable cross section is good. Only cables are burning with a smaller cross section than necessary. The tracks with a large cross section work for a long time, as they warm less.
The essence of the method
To choose a cross-section of the load on the load, fold the power of the instruments that will be connected to this conductor. It is important that all the capacities are expressed in the same measurement units - or in watts (W), or in kilowatts (kW). If there are different meanings, bring them to a single result. For translation, kilowatta is multiplied by 1000, and watts are obtained. For example, 1,5 kW will be transferred to Watta. It will be 1.5 kW * 1000 = 1500 W.Article on the topic: How to decorate a garden, household, cottage plot (50 photos)
If necessary, you can reverse conversion - watts translate to kilowatts. For this, the figure in watts is divided by 1000, we get kW. For example, 500 W / 1000 = 0.5 kW.
Further, in fact, the selection of the cable cross section begins. Everything is very simple - we use the table.
| Cable cross section, mm2 | Conductor diameter, mm | Copper wire | Aluminum wire | ||||
| Talk, A. | power, kWt | Talk, A. | power, kWt | ||||
| 220 B. | 380 B. | 220 B. | 380 B. | ||||
| 0.5 mm2 | 0.80 mm | 6 A. | 1,3 kW | 2,3 kW | |||
| 0.75 mm2 | 0.98 mm | 10 A. | 2.2 kW | 3.8 kW | |||
| 1.0 mm2 | 1,13 mm | 14 A. | 3.1 kW | 5.3 kW | |||
| 1.5 mm2 | 1.38 mm | 15 A. | 3.3 kW | 5.7 kW | 10 A. | 2.2 kW | 3.8 kW |
| 2.0 mm2. | 1.60 mm | 19 A. | 4.2 kW | 7.2 kW | 14 A. | 3.1 kW | 5.3 kW |
| 2.5 mm2 | 1.78 mm | 21 A. | 4.6 kW | 8.0 kW | 16 A. | 3.5 kW | 6.1 kW |
| 4.0 mm2. | 2.26 mm | 27 A. | 5.9 kW | 10.3 kW | 21 A. | 4.6 kW | 8.0 kW |
| 6.0 mm2 | 2.76 mm | 34 A. | 7.5 kW | 12.9 kW | 26 A. | 5.7 kW | 9.9 kW |
| 10.0 mm2 | 3.57 mm | 50 A. | 11.0 kW | 19.0 kW | 38 A. | 8.4 kW | 14.4 kW |
| 16.0 mm2. | 4.51 mm | 80 A. | 17,6 kW | 30.4 kW | 55 A. | 12.1 kW | 20.9 kW |
| 25.0 mm2. | 5.64 mm | 100 A. | 22.0 kW | 38.0 kW | 65 A. | 14.3 kW | 24.7 kW |
To find the desired cable cross section in the corresponding column - 220 V or 380 V - we find a digit that is equal to or slightly more than the previously calculated power. The column is chosen based on how many phases on your network. Single-phase - 220 V, three-phase 380 V.
In the found line, we look at the first column. This will be the desired cable cross-section for this load (the power consumption of the instruments). Cable with veins of such a section and will need to look.
A little bit about the copper wire or aluminum. In most cases, when laying wiring in a house or apartment, cables with copper cables are used. Such cables are more expensive aluminum, but they are more flexible, have a smaller cross section, work easier with them. But, copper cables with a large cross section, no more flexible than aluminum. And at large loads - at entering the house, in an apartment with a large planned power (from 10 kW and more) it is more expedient to use a cable with aluminum conductors - you can save a little.
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How to calculate the current cable cross section
You can choose a cable cross section. In this case, we carry out the same work - we collect data on the plug-in load, but we are looking for the maximum current consumed in the characteristics. Having collected all the values, summarize them. Then we use the same table. Only we are looking for the nearest greater value in the column signed by the "current". In the same line, we look at the cross section of the wire.
For example, you need to connect the cooking panel with a peak current consumption of 16 A. We will lay the copper cable, because we look in the appropriate column - the third left. Since there is no value exactly 16 A, we look at the line 19 A is the closest more. Suitable section 2.0 mm2. This will be the minimum cable cross section for this case.
When connecting powerful household electrical appliances from the flap, a separate power supply line is pulled. In this case, the selection of the cable cross section is somewhat easier - only one power value or current is required.
You cannot pay attention to a slightly smaller value. In this case, at maximum load, the conductor will warmly warm, which can lead to what isolation melts. What could be next? Can work automatic protection if it is installed. This is the most favorable option. There may be a household appliances or a fire. Therefore, the selection of the cable cross section always makes the greater value. In this case, it will be possible to install the equipment even slightly more in power or consumed current without rewriting.
Calculation of power cable and length
If the power line is long - several dozen or even hundreds of meters - in addition to the load or current consumed, it is necessary to take into account the losses in the cable itself. Typically, long distances of power lines when entering electricity from a post in the house. Although all the data must be listed in the project, you can be reinsured and check. To do this, you need to know the dedicated power to the house and the distance from the post to the house. Next, on the table, you can choose a cross-section of the wire, taking into account losses on the length.
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Table of determining the cable cross section for power and length
In general, when laying wiring, it is better to always take some margin on the cross section of the wires. First, with a larger cross section, the conductor will be warm, which means insulation. Secondly, more and more devices operating from electricity appear in our life. And no one can give guarantees that in a few years you do not need to put a couple of new devices in addition to the old. If the stock exists, they can simply turn on. If it is not, you will have to wise - or change wiring (again) or ensure that there are no powerful electrical appliances simultaneously.
Open and closed wire laying
How we all know, when passing current on the conductor, it heats up. The larger the current, the more heat allocated. But, when passing the same current, according to conductors, with a different section, the amount of heat released changes: the smaller the cross section, the more heat releases.
In this regard, with the opening of the conductors open, its cross section may be less - it cools faster, as the heat is transmitted. At the same time, the conductor cools faster, the insulation will not deteriorate. With a closed laying, the situation is worse - warm is slower thanks. Therefore, for a closed gasket - in the cable of channels, pipes, in the wall - recommend to take a cable of a larger cross section.
The selection of the cable cross section, taking into account the type of its gasket, can also be carried out using a table. The principle was described earlier, nothing changes. Just takes into account another factor.
Select the cable cross section depending on the power and type of gasket
And finally, several practical advice. Going to the market behind the cable, take a caliper with you. Too often, the declared cross section does not coincide with reality. The difference can be in 30-40%, and this is a lot. What threatens it? By burning wiring with all the ensuing consequences. Therefore, it is better to check if this cable is really the required core section (diameters and corresponding cable cross sections in the table above). A Read more about the definition of section Cable for its diameter can be read here.